Vacuum pump for vehicle

ABSTRACT

A vacuum pump for a vehicle includes: a pump housing having an internal cylindrical space, an inlet for receiving oil to be supplied to the space, and an outlet for discharging the oil from the space; a rotor eccentrically rotating in the internal cylindrical space of the pump housing; a vane rotating along the inner side of the internal cylindrical space of the pump housing; and a valve maintaining a pressure in the internal cylindrical space of the pump housing at less than a predetermined level.

CROSS REFERENCE TO RELATED APPLICATION

The present application claims the benefit of priority to Korean Patent Application No. 10-2016-0034273, filed Mar. 22, 2016, the entire content of which is incorporated herein for all purposes by this reference.

TECHNICAL FIELD

The present disclosure relates to a vacuum pump, which reduces internal pressure, for a vehicle.

BACKGROUND

In general, vehicles are equipped with a vacuum pump for operating various parts using vacuum. For example, in vehicles equipped with a diesel engine, vacuum pressure is used for a brake booster that increases a force from a brake pedal and from a turbocharger including an exhaust gas recirculation (EGR) valve, a throttle valve, and a variable nozzle, and the vacuum pressure is generated by a vacuum pump that in operated by torque from the engine through a camshaft and is supplied to various necessary parts.

Further, in the vehicles equipped with a gasoline engine, a vacuum pump is used to maintain vacuum pressure at a predetermined level or less so that an appropriate vacuum pressure is stably applied to various parts.

The existing automotive vacuum pumps, however, do not remove the internal pressure of the vacuum pumps, so the torque for operating the vacuum pumps increases and vanes are damaged by the internal pressure.

The description provided above as a related art is just for helping understanding the background of the present disclosure and should not be construed as being included in the related art known by those skilled in the art.

SUMMARY

The present disclosure has been made keeping in mind the above problems occurring in the related art, and the present disclosure is intended to propose a vacuum pump for a vehicle, the vacuum pump reducing driving torque and improving the durability of vanes by decreasing internal pressure.

According to one aspect of the present disclosure, a vacuum pump for a vehicle includes: a pump housing having an internal cylindrical space, an inlet for receiving oil to be supplied to the space, and an outlet for discharging the oil from the space; a rotor eccentrically rotating in the space of the pump housing; a vane rotating along the inner side of the space of the pump housing; and a valve maintaining a pressure in the space of the pump housing at less than a predetermined level.

The valve may include: a cylindrical valve case extending to a side to communicate with the space of the pump housing and having a hole at a top; an elastic member disposed in the valve case with a first end fixed to a side of the valve case; and a ball fixed to a second end of the elastic member to block a portion between the valve case and the pump housing when the elastic member is extended

The elastic member may be compressed when pressure over a predetermined level is applied to the ball.

The valve may be disposed at a predetermined distance in an anti-rotational direction of the vane from the outlet.

According to the vacuum pump for a vehicle that has the structure described above, it is possible to reduce the torque for operating the vacuum pump by maintaining the internal pressure of the vacuum pump at less than a reference value, and accordingly, it is possible to improve the fuel efficiency of the vehicle.

Further, the pressure applied to the vane is decreased by the decrease of the internal space, so the durability of the vane is improved and the cost maintenance of the vehicle can be reduced.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and other advantages of the present disclosure will be more clearly understood from the following detailed description when taken in conjunction with the accompanying drawings.

FIG. 1 is a view showing a vacuum pump for a vehicle according to an embodiment of the present disclosure.

FIGS. 2 to 5 are views showing the operation order of a vacuum pump for a vehicle of the present disclosure.

DETAILED DESCRIPTION

Hereinafter, a vacuum pump for a vehicle according to an embodiment of the present disclosure will be described with reference to the accompanying drawings.

FIG. 1 is a view showing a vacuum pump for a vehicle according to an embodiment of the present disclosure. Referring to FIG. 1, a vacuum pump for a vehicle may include: a pump housing 10 that has an internal cylindrical space 13, an inlet 15 for receiving oil to be supplied to the space 13, and an outlet 17 for discharging the oil from the space 13; a rotor 20 that eccentrically rotates in the space of the pump housing 10; a vane 30 that rotates along an inner side of the space 13 of the pump housing 10; and a valve 40 that maintains the pressure in the space 13 of the pump housing 10 at less than a predetermined level.

That is, the space 13 into and out of which oil flows through the inlet 15 and the outlet 17 is formed in the pump housing 10, and the rotor 20 rotates eccentrically from a center of the pump housing 10. The vane 30 is coupled to the rotor 20 and rotates with the rotor 20 in contact with the inner wall of the pump housing 10 by a spring therein for providing tensile force.

As the vane 30 rotates, the oil in the pump housing 10 is compressed and a vacuum is created. For example, when the inlet 15 is included in an area defined by the inner side of the pump housing 10, the outer side of the rotor 20, and a side of the vane 30, oil is sucked inside. Thereafter, the volume is increased and decreased while the rotor 20 rotates, in which air is removed when the volume of the oil decreases after being maximized, and accordingly, the oil can be under a vacuum state.

While the oil comes into the vacuum state, the internal pressure of the pump housing 10 increases, but when the internal pressure of the pump housing 10 excessively increases, larger force is required to operate the rotor 20 and the vane 30 may be damaged.

Accordingly, by providing a valve 40 at a side of the pump housing 10 in the present invention, it is possible to prevent an excessive increase in pressure of the space 13 of the pump housing 10. The valve 40 may be opened when the internal pressure of the pump housing 10 increases over a predetermined level.

FIGS. 2 to 5 are views showing the operation order of a vacuum pump for a vehicle of the present disclosure. Referring to FIGS. 2 to 5, as shown in FIG. 2, when a first end of the vane 30 is moved above the inlet 15 by rotation of the rotor 20, oil flows into the space of the pump housing 10 through the inlet 15. Thereafter, as the rotor 20 keeps rotating and a second end of the vane 30 is positioned higher than the inlet, as shown in FIG. 3, the volume of the oil is maximized. Thereafter, as the rotor 20 keeps rotating, the space defined by the vane 30, the rotor 20, and the inner side of the pump housing 10 is decreased, as shown in FIG. 4, and the oil starts to he compressed. Then, referring to FIG. 5, as the rotor 20 keeps rotating such that the second end of the vane 30 is positioned at an end of the outlet 17, the oil compressed in a vacuum state can be discharged through the outlet 17.

In detail, the valve 40 may include: a cylindrical valve case 43 that extends to a side to communicate with the space 13 of the pump housing 10 and has a hole 45 at the top; an elastic member 47 disposed in the valve case 43 with a first end fixed to a side of the valve case 43; and a ball 49 that is fixed to a second end of the elastic member 47 to block the portion between the valve case 43 and the pump housing 10 when the elastic member 47 is extended.

The elastic member 47 may be compressed when a pressure over a predetermined level is applied to the ball 49. For example, the elastic member 47 may be a compression spring.

The pump housing 10 forms an internal space 15 in cooperation with the ball 49, so when the internal pressure of the pump housing 10 is increased by rotation of the vane, the pressure applied to the ball 49 is increased. In this case, force is applied even to the elastic member 47 being in contact with the ball 49, and when the pressure over the predetermined level is applied to the ball 49, the elastic member 49 is compressed and the oil and air in the pump housing 10 are discharged to outside through the hole 45 of the valve case 43. Accordingly, it is possible to prevent the internal pressure of the pump housing 10 from excessively increasing.

As a result, it is possible to improve the durability of the vane 30 and reduce the force for operating the vacuum pump by decreasing the pressure peak in the pump housing 10.

Further, the valve 40 may be formed at a predetermined distance in an anti-rotational direction of the vane 30 from the outlet 17.

In the vacuum pump according to the present disclosure, the operation period where the internal pressure of the pump housing 10 increases to a maximum level is a period where the vane 30 rotates until an end of the vane 30 reaches the outlet 17 from the opposite side to the rotor 20, thereby compressing the oil, that is, is the operation period from FIG. 4 to FIG. 5.

In order to maintain a peak of the internal pressure of the space 13 of the pump housing 10 at less than the predetermined level when the oil is compressed, the valve 40 is disposed at a predetermined distance from the outlet 17 in the anti-rotational direction of the vane 30. The predetermined distance is not limited and may depend on the shape and size of the pump housing 10.

According to the vacuum pump for a vehicle that has the structure described above, it is possible to reduce the torque for operating the vacuum pump by maintaining the internal pressure of the vacuum pump at less than the predetermined level, and thus, it is possible to improve the fuel efficiency of the vehicle.

Further, the pressure applied to the vane is decreased by the decrease of the internal space, so the durability of the vane is improved and the cost of maintenance of the vehicle can be reduced.

Although the present disclosure was described with reference to specific embodiments shown in the drawings, it is apparent to those skilled in the art that the present disclosure may be changed and modified in various ways without departing from the scope of the present disclosure, which is described in the following claims. 

What is claimed is:
 1. A vacuum pump for a vehicle, comprising: a pump housing having an internal cylindrical space therein, an inlet for receiving oil to be supplied to the internal cylindrical space, and an outlet for discharging the oil from the internal cylindrical space; a rotor eccentrically rotating in the internal cylindrical space of the pump housing; a vane rotating along the inner side of the internal cylindrical space of the pump housing; and a valve maintaining a pressure in the internal cylindrical space at less than a predetermined level.
 2. The vacuum pump of claim 1, wherein the valve includes: a cylindrical valve case extending to a side of the pump housing to communicate with the internal cylindrical space, the cylindrical valve case having a hole at a top; an elastic member disposed in the valve case with a first end fixed to a side of the valve case; and a ball fixed to a second end of the elastic member to block a portion between the valve case and the pump housing when the elastic member is extended.
 3. The vacuum pump of claim 2, wherein the elastic member is compressed when pressure over a predetermined level is applied to the ball.
 4. The vacuum pump of claim 1, wherein the valve is disposed at a predetermined distance from the outlet in an anti-rotational direction of the vane. 